This invention relates to sewing machine attachments and more particularly to attachments for use in sewing fabric tubes that have a consistently uniform diameter and cross-sectional configuration throughout their entire length.
One of the major problems in the fabric sewing art is to sew a straight and even seam on any length of fabric tube particularly where the tube is of a small diameter and is used to produce spaghetti-type straps. This problem is particularly acute in the case of bias cut fabric strips utilized for many fabric tubular members because of their stretchability and flexibility in sewing articles of complex configurations. When the fabric strips are cut on the bias, i.e. at a 45.degree. angle to the grain of the fabric, the fabric tends to act like the well-known Chinese finger trap made of woven grasses or the like whereby the harder one pulls, the tighter it gets. Further, some loosely woven fabrics that can be made into desirable tubing are particularly difficult to control during sewing when cut on the bias. One important factor in home as well as in industrial sewing is the ability to create clothes and accessories which have a professional appearance. A further and equally important requirement is for the operator to be able to use a relatively simply constructed and easy to manipulate sewing machine attachment. In other words, the attachment must be a practical piece of equipment that can be readily affixed to a standard sewing machine and then operated without the user having to resort to looking up and following a complex set of operating instructions. Such an attachment is provided by the instant invention.
Various prior art devices have not proven entirely satisfactory in providing the simplified sewing machine attachment required by sewing machines used both commercially and at home for sewing simple, consistently uniform and attractive tubular fabric products. The reason for such inadequacy resided primarily in their complex design and the high level of skill required for their successful use. Further, most prior art devices were singular use devices, i.e. they were limited to producing but a single sized finished tubular product.
Prior art sewing machine attachments, such as those illustrated in U.S. Pat. Nos. 983,528, 2,570,012, 2,534,534 and 2,818,826 are representative of such complexity and the difficulties involved in utilizing such equipment. For example, they include special arbor-like elements for producing on the same equipment single size fabric tubing seamed on the outside and then inverted to conceal the seam. Thereafter, a filler material is inserted in the inverted tubing. Other sewing machine attachments for producing tubular or folded and seamed fabric items, such as are shown in U.S. Pat. No. 973,530, require extreme care in threading the cloth into and through the attachments because of the close tolerances required in precisely overlapping the edges of the fabric to be seamed. Moreover, the attachment shown in this patent is no readily adaptable for sewing differently sized tubular fabrics and in one embodiment it employs a horizontally swinging curved sewing needle that would appear to be difficult to control in sewing a straight seam. U.S. Pat. No. 2,314,202 discloses a further complex sewing machine attachment for producing biased or helically seamed tubing wherein the seam is inverted for appearance sake.
The intricate sewing machine attachment of U.S. Pat. No. 1,836,742 is intended for use in producing blind stitch piping wherein the fabric edges are folded several times and then stitched to form piping with the stitches being visible on one side only.
The several fabric guides of U.S. Pat. No. 1,157,384 are of a convoluted cross-section and not readily adaptable for producing simple fabric tubing.
Finally, the lack of a simple and readily useable sewing machine attachment for producing consistently uniformly dimensioned tubular fabric is further illustrated at pages 60 and 61 of a sewing machine manual published by the Singer Sewing Machine Company, entitled "Singer Electric Sewing Machine -206K43", copyright 1952-53. The pages referred to in this manual disclose a sewing machine attachment for sewing binding materials onto a piece of cloth wherein a multi-slotted binding scroll is employed to cause different types of binding to encircle the cloth edge to be reinforced.